/etc/at.allow exists and lists only carol. /etc/at.deny lists dave.
Determine which ordinary user may use at.
Which statement is correct?
When at.allow exists, only users listed there are normally permitted to use at; at.deny is considered when allow is absent.
Detailed explanation
Correct. carol is the only listed user in at.allow.
Correct. carol is the only listed user in at.allow.
Incorrect. The allow file is present, so deny alone does not define access.
Incorrect. The allow file is present, so deny alone does not define access.
Incorrect. dave is not listed in allow.
Incorrect. dave is not listed in allow.
Incorrect. carol is explicitly allowed.
Incorrect. carol is explicitly allowed.
Try it yourself
An example you can run in a temporary verification environment.
printf '%s
' carol | grep -Fx carolExpected result
carolKey points
- at.allow has priority
- Only listed users are allowed
- deny is fallback
Notes
- Environment: POSIX grep / 模擬一覧のみ
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.